Lynden Dorval tried to talk himself out of it. He understood the stakes.

You push back against school administrators, swim against school policy and you become a marked man, an “insubordinate” problem teacher with a bull’s eye on your back.

But the problem was the more he thought about it, the more Mr. Dorval, a physics teacher at Ross Sheppard High School in Edmonton with 35 years’ experience, became convinced of what he had to do — even if it cost him his job.

“I knew it was going to be a lot of stress,” he says. “But I just couldn’t talk myself out of it. It was the right thing to do.”

[np-related]

What he did, over the past 18 months, was what he had done for over three decades when a student didn’t submit an assignment, skipped a test or missed an exam: he pulled out his red…